Indications for closed thoracic drainage include: I. Spontaneous pneumothorax, with lung compression less than 30%, can be treated conservatively. Lung compression greater than 30%, need to perform closed chest drainage; Second, traumatic hemopneumothorax, the hemopneumothorax volume is larger also need to place closed chest drainage, the purpose is to observe the amount of bleeding, how much bleeding per hour, if the bleeding volume is greater than 200ml per hour, more than three consecutive hours with the indication of open chest exploration; Third, medium to large amount of pleural effusion, need to perform closed chest drainage; Fourth, a variety of thoracic surgery Chest drains need to be placed later for the purpose of observing the amount of bleeding and allowing lung reopening.